I haven't contacted Power skin yet, I did, however, remove the case for the USB transfer. The supplied USB cable is only about 3-4in long, kind of inconvenient. The Samsung charging/USB cable works better and it also charges the case.
Yesterday I tried a little experiment, charged both phone and case to 100%, 12 hours later the phone was still at 100% and the case was down to 50%
I read the posts on the other forum and I see that most don't like the bulk, I have no problem with the size and charging time is about the same as the in phone battery. I'll have to wait and see if any issues come up after using it for a period of time.
One other odd thing is once the phone is charged to 100% it gives a notification that i should unplug the charger. I can turn off the PowerSkin, however, and just use the phone battery.